Small
Hive Beetle

Introduction

The small hive beetle (SHB),
Aethina tumida Murray, is an emerging and invasive pest of the European honey
bee. The SHB can impact colony health and damage beekeeping equipment.

Spread
of Small Hive Beetle

The SHB is native to Sub-Saharan Africa and has spread
into many regions of the globe in recent years. The SHB was first discovered in
USA in 1998 (Florida) and has become well established in most states across the
USA, with particularly large populations in warmer, coastal states. The SHB was
first discovered in Australia in 2002 (New South Wales) and has since become well
established spreading along the Eastern Coast.

In Canada, the SHB was discovered
in Manitoba (2002 and 2006), Alberta (2006) and Québec (2008, 2009). In
the Prairie Provinces, control measures were taken to control the pest and SHB
failed to establish a population. It is still to be determined whether SHB has
been able to establish a resident population in one region of southern Quebec.

In September 2010, SHB was identified in southern Ontario. At present,
it remains unknown whether SHB will establish a resident population in Ontario.

Life Cycle and Biology

The SHB is a member of the "sap beetle",
family Nitidulidae. Like all other beetles, the SHB goes through complete metamorphosis
from egg to larvae to pupae to adult. The timing of full development varies from
21 to 94 days depending on the temperature and humidity.

Adult SHB will
seek out honey bee colonies for shelter, food and breeding area for their developing
young. The eggs of the SHB are small (1.4 x 0.26 mm), pearly white and laid in
clusters in cracks and crevices of the hive. Eggs hatch in three to six days.

Larvae grow to 11 x 1.6 mm before pupation. Larvae resemble grubs and are
white to beige in color with a brown hardened head, three sets of legs and rows
of brown spines along the length of the body (Figure 1). Larvae are typically
found clustered together in cells of the honey comb, often immersed in a film
of fermented honey.

The larvae are the most destructive life stage of the
SHB in terms of damage to honey bee colonies. Larvae feed on honey bee brood,
pollen, honey and tunnel through wax comb consuming protein required for their
development. Larvae defecate in the honey comb, causing the honey to ferment and
spoil. Like other sap beetles (i.e. Nitidulids), SHB are closely associated with
a specific strain of yeast (Kodamaea ohmeri) that may aid in feeding.

After
10 to 28 days (average 16 days) the larvae will leave the colony, burrow into
the soil (on average 10 cm deep and 30 cm from the colony entrance) to pupate
in the soil (10 to 60 days, average 25 days). Lighter, sandier soils are most
suitable for SHB pupation. Adults are reddish brown to black (4 to 7 x 2 to 3.5
mm) with clubbed antennae, shortened wing coverings that do not extend the full
length of the abdomen and a distinct crescent moon shaped structure behind the
head (Figure 2).

Adults are long lived (up to six months), can disperse
by flying (10 to 14 km) and have a tremendous reproductive capacity. The dispersal
of adults is aided by movement of infested honey bee colonies and beekeeping equipment.
In addition, SHB are not restricted to honey bee colonies, being able to survive
on rotting fruit and can go without food for up to 10 days in the adult stage.
This may also contribute to their dispersal. In winter, adult SHB can live within
the honey bee cluster.

Figure 1. Larvae

Figure
2. Adult

Impact

Weakened and compromised honey bee colonies are
at greatest risk of SHB damage. However this may also include healthy nucleus
colonies, mating nucs and queen banks. A honey bee colony without a strong population
of worker bees to protect the exposed food stores and bee brood can succumb to
a rapid increase in numbers of SHB larvae. This will further stress the colony
as SHB larvae will feed on brood, spoil food stores and foul the environment of
the colony.

In severe infestations of SHB, colonies may perish or abandon
the hive. Although adult SHB may be present in strong, populous colonies; the
development of large numbers of SHB larvae is often restricted by the activities
of the honey bee workers.

In dead honey bee colonies or exposed beekeeping
equipment, SHB infestations can increase dramatically as there is a large source
of larval food and no protection. Similarly in honey houses and extracting facilities,
SHB can spoil honey when honey comb is exposed for long periods of time. It is
recommended that beekeepers promptly extract any exposed honey comb and clean
facilities immediately after extraction. Wax cappings should also be stored in
beetle tight containers and rendered as soon as possible.

Detection

Adult
SHB are often found in dark, tight spaces in the hive environment. However, they
may be encountered

anywhere in the colony, especially when present at high
densities. Adults are typically found on the underside of the inner cover, tops
of frames and on the bottom board. Adult SHB will move quickly away from light,
so it is important to make a quick visual scan as soon as the colony is opened.

Adults can also be detected by a variety of traps, which typically have
tight spaces that attract SHB adults. Two of the most common traps are corrugated
cardboard or plastic inserts and traps containing oil. The larvae of SHB are typically
found on the surface of unprotected comb and at higher densities on the bottom
board. Symptoms of the SHB larvae include clusters of larvae feeding in the comb
and fermented honey oozing down the surface of the frame (a.k.a. "sliming")
(Figure 3). This can be seen in both field colonies and in extraction facilities.

Figure
3. Comb

Management

There is only one registered treatment
for SHB in Canada, CheckMite+ (see treatment recommendations on the label
for SHB and follow all label instructions).

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